Quality in Requirements Analysis

Chapter 13: Quality in Requirements Analysis

• Learning Goals:

  • Accessibility, comprehensiveness, understandability, ambiguity, consistency, prioritization, security, completeness, testability, traceability of requirements.

• Key Qualities of Requirements:

  • Accessibility: Ease of access to requirements; metric from 0 (long access time) to 10 (fast access).

  • Comprehensiveness: Covered by resource availability and prioritization; metrics for requirements implemented vs targeted requirements.

  • Unambiguity: Defined by clarity of meaning; metric based on a scale of 0 to 2.

  • Consistency: No contradictions; assessed using percentage of consistent requirements.

  • Prioritization: Metrics for distribution of priority levels across requirements.

  • Self-Completeness: All necessitated requirements must be present; assessed by number of missing requirements.

  • Testability: Clarity and capability of being tested; assessed with specific examples of requirements written clearly.

  • Traceability: Requirements must be traceable to their implementations; assessed on a scale of 0 to 100 based on traceability score.

• Metrics:

  • Comprehensiveness:

  • ext{Percentage implemented} = 100 * \frac{# \text{ implemented}}{T}

  • \text{Percentage targeted} = 100 * \frac{(# \text{ implemented}) + (# \text{ top priorities})}{T}

  • Ambiguity:

  • \text{Ambiguity metric} = 100 * \frac{\sum \text{unambiguity scores}}{2 \times \text{number of requirements}}

  • Consistency: Percentage of requirements that are consistent.

  • Prioritization: Metrics based on deviation in priority distribution from a balanced set (high/medium/low).

  • Self-Completeness: Ratio of missing necessary requirements to present requirements.

  • Testability: Clarity of requirements that can be determined and tested.